Field of the Invention
The present invention relates to display technology, and more particularly, to an array substrate, a display device and a drive method for the same.
Description of the Related Art
Thin Film Transistor-Liquid Crystal Display (TFT-LCD) is widely used in these electrical products such as TV, mobile phone and displayer, etc., and dominates in the field of panel display, because it has the advantages of stable quality, realistic picture, elimination of radiation, space saving, and power consumption saving, etc.
Refer to FIG. 1, in the TFT-LCD, there are gate lines and data lines disposed in an array substrate and intersected with one another, and, a plurality of pixel units is defined by the intersected gate lines and data lines. In a row of the pixel units, three neighboring pixel units constitute one pixel. All these pixel units are divided into a number of pixel regions by columns, and, one pixel region is driven by one corresponding data driving unit. As shown in FIG. 1, the data driving units SDn and SDn+1 are connected with their corresponding data lines, respectively. In each column of the pixel units, the two adjacent data lines Dn and Dn+1 are connected alternately in row with the pixel units of the same column, respectively. Each pixel unit includes a thin film transistor which is driven by signal from the gate line, and a pixel electrode driven by signal from the data line. Generally, there is a capacitance effect in the array substrate and a memory capacitor is formed between a common electrode and the pixel electrode. During the charging and discharging of the memory capacitor, due to capacitive coupling, voltage on the common electrode fluctuates. Moreover, polarization of the liquid crystal molecules occurs since the liquid crystal molecules rotates in one direction longtime. Therefore, there requires polarity inversion of the liquid crystal molecules from one frame to another frame.
In the prior art, the drive modes to polarity inversion mainly includes frame inversion, row inversion, column inversion, and, dot inversion, etc.
In a greenish test picture shown in FIG. 2, columns of the pixels in dark and columns of the pixels in bright are alternated in column with one another. In order to achieve polarity inversion in a manner of dot inversion while effectively reducing logical power consumption of the liquid crystal panel, Z inversion is usually used for arrangement of the pixels, and column inversion is usually used for output of the common electrode. However, the abovementioned drive modes for polarity inversion have the disadvantages of: distortion of color will occur during displaying of the liquid crystal panel since voltage difference applied on the pixel electrode changes when the voltage on the common electrode is increased or decreased. Taken the first row of the pixels as an example, in a region where it is in a bright state (contrary to a dark state) after being charged, in each pixel, red pixel unit (R) and blue pixel unit (B) are in positive polarity while green pixel unit (G) is in negative polarity. Because two pixel units are in positive polarity while one pixel unit is in negative polarity when there is data signal from the data lines, voltage on the common electrode fluctuates upwardly, correspondingly, in the whole row of pixels, the voltages on these common electrodes fluctuate upwardly. In one pixel under the bright state, since the red pixel unit (R) and blue pixel unit (B) are in positive polarity, voltages on the corresponding common electrodes fluctuate upwardly, resulting in decreasing the voltage differences on the red pixel unit (R) and on the blue pixel unit (B) and correspondingly lightening the colors on the red pixel unit (R) and blue pixel unit (B); while, since green pixel unit (G) is in negative polarity, voltage on the corresponding common electrode fluctuate upwardly, resulting in increasing the voltage difference on the green pixel unit (G) and correspondingly brightening the color on the green pixel unit (G) due to relative larger rotation offset of the driven liquid crystal molecules caused by the increased the voltage difference. In this way, the green pixel unit (G) is over brightened and the color of the green pixel unit (G) is deepened, which renders this pixel greenish. For similar reasons, these other green pixel units (G) are greenish, and as a result, the displaying of the whole liquid crystal panel is greenish. Such greenish is more serious when voltage on the common electrode fluctuates in a more acute manner.
In order to alleviate such greenish displaying, at present, generally a method for compensating voltage on the common electrode while reducing the memory capacitance is adopted. However, for the liquid crystal panel with high refresh rate, voltage on the common electrode fluctuates acutely, in this case, the effect is not too apparently even if the abovementioned method is adopted. Furthermore, with the development of technology, the liquid crystal panel will have a higher refresh rate, which can be 120 Hz, or even, 240 Hz. Therefore, the greenish displaying becomes the bottleneck for large-size TFT-LCD with high refresh rate recently.